Conversion of ethylene



' 1945- v. N. IPATIEFF ET'AL v2,339,780 I CONVERSION OF ETHYLENE Filed June 22, 1942 N WNDNURNN M], Mimi/'1,

atented Nov; 27,1

NITED s'rArss PATE CONVERSION OF ETHYLENE Vladimir N. Ipatieif and Vladimir Haensel, Chicago, Ill., assignors to Universal Oil Products Company, Chicago, Ill., a corporation of Dela- Application June 22, 1942, Serial No..447,958

9Claims.

Thisinvention relates to a process for converting ethylene into propylene, butylenes, and normally liquid hydrocarbons of gasoline boiling range. More specifically, the process is concerned with the treatment of ethylene or an ethane-ethylene fraction in the presence of a granular refractory catalytic material. f

In one specific embodiment, the present invenof. silica, alumina, zirconia, and/or thoria with tion comprises a process for treating ethylene or yon ethane-ethylene fraction at a temperature of from about 250 to about 550 C. in the presence of a calcined composite catalyst comprising silica and zinc and at least one oxide from the group utilization of ethylene hasnot progressed as raps idly as utilization of higher oleflns, probably because processes were not developed previously whereby ethylen could be controllably converted into propylene and butylene as well as into normally liquid oleflnic hydrocarbons. The present invention is concerned particularly with a process in which the conditions of operation are controlled to produce normal butylenes' which themselves are readily polymerizabl either thermally or catalytically or which may be converted into butadiene by catalytic dehydrogenation or by chemical means.

Catalysts utilizable in the present process are formed by compositing a solid polymerizing catalyst comprising essentially an association of oxides of silicon, aluminum, and zirconium with zinc and/or zinc'oxide. comprising an association of aluminum oxide and silicon oxide may 'consist of a synthetically prered silica-alumina mixture or a certain raw or acid-treated clay. Preferred silica-containing catalyst components such as silica-alumina, silica-jalumina-zirconia, silica-zirconia, and other so-called silica base caalysts may be prepared by a number of alternative methods including the simultaneous or successive precipitation of hydrogels of silica and alumina followed by wasfhing, drying, and calcination treatments. Catazinc and/or zinc oxide. Catalysts utilizable in the present process are preferably calcined by heating in air at an elevated temperature prior to being introduced to the reaction zone in which ethylene is convertedinto propylene, butylene,

and higher molecular weight hydrocarbons. Al-

though the nature of the catalyst is not understood completely, the calcination treatment may activate the silica-containing composite and also convert a portion of the zinc' into zinc oxide which apparently has a beneficial influence on ethylene conversion reactions as herein described.

The process of the present nvention is preferably carried out in a continuous manner to control the reaction so as to obtain not onlynormally liquid polymers but also substantial yields of propylene and butylene. In. can'ying out this process, ethylene or-a mixture such as one comprising essentiallyethane, ethylene, methane, and

hydrogen is compressed to a pressure of from about 300 to about 1500' pounds per square inch and passed through a preheating zone, after which the heated gas is directed through a re- A catalyst component actor containing granular catalyst as herein described. The reactor containing the catalyst through which the ethylene is passed is maintained at a, temperature of from about- 250 to about 550 C. The catalyst employed in the process makes the catalytic surface very large in comparison with the surface of the walls of the reactor.. The preferred size of the catalyst particles' depends upon the t pe 01' operation to be carried out, that is, whether the catalyst is utilized in the form of a fixed bed, as above referred to, or whether it is employed as fine powderwhich is utllizable either as a slurry or in a type 01' treatment generally referred to as fluid type operation. when utilizing a fixed bed of 7 catalyst in laboratory size equipment, it is generally preferable to employ catalyst particles of about 8 to 14 mesh size in order to obtain good contact between the reactionmixture and the catalyst.

lysts are also formed by compositing hydrogels 55 The reaction product obtained in the present process is fractionally distilled and separated into a mixture of unreacted ethylene and ethane, a mixture of hydrogen and methane, the latter materials being either present in the charging stock or formed during the process, and a fraction comprising essentially propylene, butylenes, and higher boiling hydrocarbons. The ethaneethylene fraction is suitably recycled to the reaction zone and the mixture of propylene, butylcues, and higher boiling hydrocarbons-is further NT orrlcsf comprising essentially a mixture of higher boiling hydrocarbons.

The present process of treating ethylene or an ethane-ethylene mixture in the presence of a catalyst as herein described has several advantages over the thermal treatment of ethylene or of an ethane-ethylene fraction in the absence of a catalyst. By the use of the present process,

formation of carbon or a hydrocarbonaceous deposit within the reactor is kept low in contrast to the results obtained when employing a reactor containing no catalyst or one containing an assoelation of aluminum oxide, silicon oxide, and zirconium oxide without the addition of zinc and/or zinc oxide as herein set forth. The product formed in the present process is substantially oleflnic in character and contains considerable proportions of higher gaseous oleiins, namely propylene and butylenes with particularly large amounts of normal butylenes.

.By varying the operating conditions and pref erably by'lowering the pressure, the ratio of normally gaseous olenns to normally liquid claims may be increased considerably. The catalyst used in the fixed bed type of operation provides, for a 1 rapid distribution of heat and also makes a high ratio of the filler surface to the metal wall surface of the reactor. The presence of a large surface of catalyst within the reactor in comparison with the relatively small surface of the metal walls make it possible to eliminate to a very large extent the'undesired dehydrogenation and hydrogenation reactions, which in the absence of the catalyst would tend to convert a substantial pro-Z portion ofthe ethylene into normally aseous paraflins, some of higher molecular weight than ethylene. Thus. it is possible in the presence of valve H to coil II in heater l8 and thence through lines I! and II and valve It to reactor i'l containing catalyst as hereinbeiore set forth. The heated ethane-ethylene fraction may also be directed from line H through valve II to a second reactor I! also containing catalyst. Although only two reactors are shown in the drawing, more than two may be employed either in parallel or in series as desired. Reactors l1 and it may be utilized in series by conducting the reaction mixture from reactor II through lines a 20 and 22 and valve 28 to line It beyond valve I 8 and thence to reactor II. In order to effect this type of operation, valves II and II are kept, closed. The resultant reaction mixture is directed from reactor it through line 24, valve 25, and line ill to fractionator 20. In case reactor l1 and is auto be operated in parallel, valve 23 is closed. The reaction products being discharged from reactors i1 and it are directed to fractionator 26 of suitable design for separating said products into a mixture of light gases com-' prising essentially hydrogen, methane, ethane,

and ethyiena'a C3-C4 hydrocarbon fraction containing substantial proportions of propylene and butylenes, a normally liquid hydrocarbon fraction of gasoline boiling range, and a higher boiling mixture of liquid hydrocarbons which may be referredto by the term residue. Fractionator which is shown as equipped with reboiler coil 21 may also consist of more than one fractionating column as may be necessary to effect the desired separation.

The mixture of light gases comprising essentially hydrogen, methane, ethane, and ethylene is directed from the top of fractionator 28 through line 2! containing valve 2! to compres-.

tial proportion thereof is directed from line 8! the catalyst to obtain substantial yields of higher I molecular weight normally gaseous olefins including propylene and butylenes, the latter comprising both isobutylene and normal butylenes.

Propylene, butylene, and normally liquid products resulting from the catalytic treatment of ethylene or an ethane-ethylene fraction may be separated from the unconverted ethylene-containing gas and the latter may be recycled to further con- .version in the preseneeof the composite catalyst I as hereinbeforc set forth Further features and advantages :of the present invention will b evident from consideration of the following description of one characteristic operation of the process illustrated by the flow shown in the attached diagrammatic drawing.

Referring to the drawing, a hydrocarbon fraction comprising essentially ethylene or ethylene and ethane and small amounts of methane and hydrogen which were not removed due to limitations of previously employed fractionation equipment, is directed through line i and valve 2 to compressor 3 which discharges t rough line I and valve ii into fractionator 8 provided with reboiler coil I and of conventional design in which light gases such as hydrogen and methane are separated from hydrocarbons containing 2 carbon atoms per molecule. Alternatively thi separation may be effected in absorption and stripping equipment not illustrated in the diagrammatic drawing. The light gases are discharged from fractionator 8 through line 8 and valve 9, and a fraction comprising essentially ethane and ethylene or ethylene is directed through line II and andvalve ll.

sor III which discharges through line 3i containing valve I2. While a portion of this mixture may be discharged through valve 32, a substanthrough recycle line I! and valve it to line I already mentioned charged ethane-ethylene fraction is introduced to fractionator 0, already mentioned. The C2-C4 hydrocarbon fraction formed in the process and containing a high proportion of olefinic hydrocarbons is discharged from fractionator ll through line I! and valve it to cooling and storage, not illustrated in the drawing. Normally' liquid hydrocarbons of gasoline boiling range are directed from fractionator It through line 81 and valve ii to cooling and storage. Hydrocarbon material boilinghigher than gasoline and generally referred to as residue is withdrawn from the bottom of fractionator it through line I In carrying I ethane-ethylene mixture may be passed through one reactor until small amounts of carbon or bydrocarbonaceous material deposit upon the catalyst and then the motion mixture may be directed to the other reactor while the carbonaoeous deposit is burned from the catalyst in the first named reactor. in this way, each catalytic reactor is used alternatively and each processing period is followed by a period of catalyst reactivation; The attached drawing does not illustrate the additional equipment necessary for effecting such catalyst reactivations.

The following example is introduced as characteristic of the results obtained in the present process, although these data are presented with no intention of thereby limiting the generally broad scope of the invention.

and through which theout the present process the heated respectively, (1) a composite oi-ca.-

al and zirconia and (2) a composite oi silica, 31 m is: an zinc @3151; which had been calcined in air for one hour at 400 C. during which e some mnc oxide was formed in the composite. The silica-alumina- 1 composite consisted of about loo-molecular propertions oi silicon omde. two molecular. proportions of co:- oxide, and tour molecular, proportions of zirconium oxide. For use in run 2, 48% by weight of the powdered silica, alumina, and composite and 48% of zinc dust were intimately mixed with'4% oi powdercdrosin,

after which the mixed powder was formed into about 95% by volume boiled below about 220 C. and had an octane number of 80. a

The foregoing specification and example indicate the character and value oi-the present invention, although it is not intended that either section should unduly limit the generally broad scope of the invention.

We claim as our invention: l 1. A process for converting ethylene into substantial yields of butylene which comprises reacting ethylene in the 'presence of a calcined composite catalyst comprising silica metallic zln alumina and zirconia.

8x8 mm.cylindrical pelletsbymeans oiapilling machine. These pellets were then calcined in air as above indicated and utilized as reactor filling material. The silica-alumina-zirconia composite all M m If calcined before use.

of ethylene- Run No.

1 Cal inad u- .i v mess I m and m ii i a -girco g andcincdust 325 an 1,000 1.0m

a7 as ass zao 1L5 m2 00.0 ass 8.7 0.1 as 1.0 38.5 00.]. mo as can 'eu o.s 1.4 as 4.1 2.5 2.0

" 11.2. see

54.0 sac than the'prwence of. the silica-al- 1 zirconla composite.

The liquid product formed in the nee of the catalyst of present invention essentially mono-oleflnic hydrocarbons including those con atoms per molecule. 01 the liquid by .4103

11 irom 5 to 12 and O91 puct, 75% oi 1-filling material in runl was 2. A process for producing substantial yields 01 butylenes and gasoline which comprises subjecting ethylene to a temperature of from about 250 to about 550 C. under a pressure of from about 300 to about 1500 pounds per square inch in the presence of a solid granular composite comprising essentially silica, metallic zinc, zinc oxide, alumina and zlrconia.

3. A process for producing substantial yields of butylenes and gasoline which comprises subjecting an ethane-ethylene fraction to a temperature of from about 250 to about 550C. under a pressure of from about 300 to about 1500 pounds per square inch in the presence of a solid granular composite comprising essentially silica, me-

alumina, sirconia, zinc oxide, and metallic zinc.

5. A process for producing substantial yields oi butylenes and gasoline which comprises subjecting ethylene to a temperature of from about 250 to about 550 C. in the presence of a solid 40 granular composite comprising essentially silica,

alumlna, mic omde, and metallic zinc.

0., A process for producing substantial yields of butylenes and gasoline which comprises sub-- iecting ethylene to a temperature of from about 250 to about 550 C. in the presence of a solid sranular composite comprising essentially silica. zirconia, zinc oxide, and metallic zinc.

7. A process for producing substantial yields I of butylenesand gasoline which comprises sublooting an ethane-ethylene fraction to a temperametallic mac.

ture oifrom about 250 to about 550 C. in the presence of a solid granular composite comprising tially silica, alumina, zirconia, zinc oxide,

and metallic zinc.

8. A pr for producing substantial yields of butylenes and gasoline which comprises subfleeting an ethane-ethylene fraction to a temperature of from about 250 to about 550C. in the presence of a solid granular composite comprisins essentially silica, alumina, zinc oxide, an metallic zinc.

t for producing v substantial yields of butylmes and gasoline which comprises subicctins an ethane-ethylene fraction to a temperature of from about 250 to about 550 C. in the presence of a solid granular composite comprisins tially silica, zirconia, zinc 0x1 de, and 

